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Updated: June 11, 2025
On the peninsula of Sabbioncello they lie partly in one and partly in the other direction. The former connection between the islands and the mainland is proved by the remains of rhinoceros, horse, and stag in the diluvial bone breccias of Lesina, and the survival of the jackal in Giuppana, Curzola, and Sabbioncello.
In 1863 and 1866 he had been among the Nagelflüh of Northern Switzerland, studying the puddingstones and breccias. He saw that the difference between these formations, in their structural aspect, and the hand-specimens in his collection of pisolitic and brecciated minerals was chiefly a matter of size; and that the resemblances in form were very close.
These strata are less connected by alternation than by opposition. Porphyritic breccias which envelope the quartzose porphyries. The gem-salt oscillates from zechstein to muschelkalk. Tertiary strata, showing a much smaller number of dicotyledonous plants. These alternations and transitions appeared to me less common in the littoral Cordillera of Venezuela than in the Sierra Parime.
The felspathic lavas, with their associated beds of tuff and breccia, rise into some of the grandest mountain crests of North Wales, such as those of Cader Idris, Aran Mowddwy, Arenig and Moel Wyn. A similar series is also represented in Ireland, ranging from Wicklow to Waterford, forming a double group of felstones, porphyries, breccias, and ash-beds, with dykes of basalt and dolerite.
The hill of calcareous breccias, which we have just mentioned as having once been an island in the ancient gulf, is covered with a thick forest of cylindric cactus and opuntia. Some of these trees, thirty or forty feet high, are covered with lichens, and are divided into several branches in the form of candelabra.
Volcanoes of earlier date than the sandstone and calcareous rocks have been for ages extinguished; those which are yet in activity are in general surrounded only with breccias and modern tufas; but nothing hinders us from admitting, that the archipelago of the Canaries may exhibit some real rocks of secondary formation, if we recollect that subterranean fires have been there rekindled in the midst of a system of basalts and very ancient lavas.
The total thickness of the volcanic flows in this locality is as much as 4000 feet." It is to these breccias we owe the volcanic appearances in the Truckee River Canyon, a few miles before reaching the Lake. There are several layers of the andesites breccias at the head of Bear Creek Canyon, above Deer Park Springs.
After giving no small weight to the arguments of M. Desnoyers, and the writings of Dr. Buckland on the same subject, and myself visiting several caves in Germany, I came to the opinion that the human bones mixed with those of extinct animals, in osseous breccias and cavern mud, in different parts of Europe, were probably not coeval.
These breccias must have issued from fissures near the summit of the range and were, either before their eruption or at the time of issue, mixed with enormous quantities of water, forming mud flows sufficiently fluid to spread down the slope for distances of fifty or sixty miles.
Professor Ramsay refers the angular form and large size of the fragments composing these breccias to the action of floating ice in the sea. These masses of angular rock, some of them weighing more than half a ton, and lying confusedly in a red, unstratified marl, like stones in boulder-drift, are in some cases polished, striated, and furrowed like erratic blocks in the moraine of a glacier.
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